1.8 L-Jet to 2.0 L-Jet. Any advice? Options

[mapguy]

Howdy,

I have just torn down a bone stock '74 1.8 L-Jet from another 914 with plans to build it back to stock. Plan is to drive my 914 with this engine while I build the original 2.0 the way I want it. I get experience building my first type 4, and get my teener back where it belongs. On the road.

I have the parts available to swap out the crank, rods, and P/C from a '76 2.0 to make it a 2.0 L-Jet. I'm very tempted to do this, as I rarely turn down cheap horsepower! No replacement for displacement, right?

Any land mines I should look out for? Main concern for me is the stock L-Jet system. I understand I might have to tune the MAF for the extra displacement, but I can't find anything discouraging me otherwise. I found an article that details a 3-step process for MAF tuning, but am too lazy to look up the link. Do tell if you know something I don't.

More details:

As implied, stock '74 L-Jet system
Stock '74 1.8 heads (41x34, I believe)
web cam 142/lifters
necessary machine work
Cylinders honed and new rings (I have a set of 94s in excellent condition)
Full re-seal on engine and all peripherals
New fuel lines, vacuum lines, etc etc...

One other thing, I haven't built many engines, but all the ones I've been involved in pop through the intake when first firing them off, and one in particular did it several times before finally lighting off (my old bus engine was a PITA to get running first time). Won't this be dangerous for the MAF on first start? All my experience is with carbed engines. Does this just not happen on FI engines?

Any advice is greatly appreciated.

[MartyYeoman]

I thought the TPS is a binary switch, only activated at WOT.

[MrKona]

I thought the TPS is a binary switch, only activated at WOT.

Marty - I just put a multimeter on the leads and it looks like you are correct. I saw resistance changes (just moving it without installing on the TB) only at the closed and near full throttle position. I guess that's why it's called a throttle position switch. (IMG:style_emoticons/default/biggrin.gif)

Unfortunately, the L-jet TPS stops the full range of motion of the plate when using the shaft from the vanagon TB.

I tried turning the TPS around 180 degrees. In that case, the TPS allows the TB plate to move from closed to full throttle position, but there are no resistance changes.. The mix/match of components appears not to engage the TPS to the full throttle position, even when the vanagon TB plate is at full throttle position in the TB.

I hope I'm explaining this clearly everyone. Let me know if pictures are needed.